This invention relates to a dry process for surface treatment of solid products, and an apparatus therefor. More particularly, the invention relates to a surface treating method which is capable of realizing high throughput surface process especially suited for the production of semiconductor devices, and an apparatus therefor.
A surface treating apparatus capable of realizing dry process suited for the production of semiconductor devices is disclosed in Japanese Patent Application Kokai (Laid-Open) No. 35521/87. In this apparatus, a pertinent gas is heated in a furnace of high temperature to activate the gas chemically, and the activated gas is ejected into a vacuum to form active particle beams. These active particle beams are applied to the surface of the workpiece to perform the desired surface treatment. In this apparatus, the operations are carried out by controlling the internal pressure of the furnace at about 1 Torr while keeping the vacuum to the order of 10.sup.-3 Torr or below.
According to said prior art techniques, the gas particles which have reflected off the workpiece surface without undergoing a reaction are evacuated out and play no part in the surface treatment. There are occasions where some of the active particles, even though impinging on the workpiece surface, reflect off the surface without reaction, and in such locations, if the workpiece temperature is low, most of the reflected particles become inactive and are discharged out. Needless to say, the non-activated particles won't react even if impinging on the substrate surface.
Thus, in the prior art, little consideration has been given to the efficient utilization of gas particles for the surface treatment, and the problem of low throughput has remained unsolved.